Hypodermic syringe



Nov. 8, 1960 E. s. v. LAUB HYPODERMIC SYRINGE Filed DSG. 26, 195'? zev Z3 c zo' J0 a 24 www J4 l ,Z3 yf g zz@ WMM The Yinvention relates to hypodermic syringes! and'has'f asian object the provisionl of a simple inexpensive'syr'ingeY which may be prepared in ladvance Vof expected or possi ble use, used-once, and-discarded"withlsmalleconomic loss, such loss being more thanUcompensated-for by' conveni'euce and time-Saving. l

Av further object of my invention is to' provide ahy'podermic syringe whichy may bevery quickly placedinf condition for immediate use, although normally` carried' in sealed and sanitary condition and provided with a standard measure'of a medicamentto be injected.

A more specific object of my invention-is to take advantage of the'elastic qualities of'available plastic ma terials to provide*frictionseals-forboth the needleofthe syringe and for the-'plungerof the'syringe.

Other objects andadvantages Iofmyvv invention will become apparent as -the--following-'specication proceeds.

-In the accompanying drawing, illustrative of a presently preferred embodiment of my invention,

tFig. 1 is4 a'perspectiveviewof a sealed syringe'asit would appearprior'to beingmadeready-for use;

Fig.` 2 is a longitudinal sectional view'on" the line 2v2 of Fig. l;

Fig. 3 is an end view from the left of Fig. 2;

Fig. 4 is a longitudinal sectional View on the line 4--4 of Fig. 2, the syringe being shown just after, rather than prior to use and being changed in orientation 90 degrees from the view of Fig. 2; and

Fig. 5 is a longitudinal sectional view of a modiiied form of seal for the hypodermic needle.

Having reference now to the details of the drawing, I have shown in Fig. l a cylinder having an open end 11 and a closed end 12. From the closed end 12 there protrudes a hollow needle 13. The cylinder 10 is preferably made of plastic and more specically is preferably, although not necessarily, of a grade of polyethylene plastic known as Marlex. This particular grade of polyethylene has the advantage that it is translucent, permitting a liquid level within the cylinder to be ascertained, and is slightly elastic. It is, for example, used to make plastic pinch bottles, which exude their contents like an oil can when squeezed or pressed but return to and retain their original shape. Marlex also has the advantage of being able to be sterlized by autoclaving, instead of chemically. It also has the advantage of having, on unnished surfaces, a high co-eflicient of friction on steel. The latter quality makes it capable of retaning a steel needle and, as will be presently shown, of capping such a needle. However, I do not intend to be limited to any particular brand of plastic, as new plastics are being constantly developed, having the requisite quality, or some of them, which are satisfactory for my purposes.

The needle 13 is preferably steel, but it too may be of plastic and may be integrally molded with the cylinder 10. If of steel, it may be secured in the closed end 12 by means of a small bulb 14 on its encased end,

Kyways 15` exnalongimdinauy in the cylinder 1Q! from"theopen 'end 11Y to a pointl approximately half-'- way to theE closed end`12'. The keyways 15 may 'bel-any1 convenient number, one, two,`orv three for example,l two'- keyways being shown (see Fig. 3). They open end'11 is rimmed by laterally outstandingl ilangesVA` 1'6"'5 on the one side of 'each' of 'the 'keywayslSj on the-mypasiteside of the keyways 15 thel wallv of-'the cylinder l'exten'ds 'longitudinally beyond theA flanges to form stops'17 which stop'lrotationvofiaplunger 201.' The'cor-`` arcani ners"18 lof therflanges 'x16' are "rounded to 'permit' actionby-a member sliding'acrosseth'em.

The plunger 20 ts slidably within the cylinder 14k-and* has at its outer end 21 keys 2,2 which may be thesam'e in Ynumberl :as the keyways -15,' within which they t slidably, two -keys"22L being shown'. Theikeysv'22'extend` later'`ally1`fro'rn\the"y end 21V of the'plunger 20t and-'each`- is providedwith a' iinger' 23` atV the -level of 'the outer periphery of'the ange 16.' The nlingers 23'extend-tofwards the innerend 24-of the plunger`20 so as to crossi over 'the ilanges- 16 and then turn inwardvv as at'25 :tof

grp'the `llanges" l'betweenthemv andthe keys 22. It'

will be seength'atthe ronndedcorners 18-on` the Ailang'esfy 16y permit the iingers`23 to `ride up'-onv the anges" 16 and fto exertean inwardA pressure` thereon.

Tire end 22l`ofth'e plunger 20' extends a shortdis'tance beyond :the keyways 15 when the keys '22 are in contactf Withthellange's' 16, sufficiently so` as to produce a sealinglcontact between the plunger 20jand the wall of the I cylinder 10 unslotted by the keywayslS," and"so also as tov leave achamber" for' containing l'medicaments which the syringe' is to administer.

ThefplungerZ "is made of'rMarlex polyethyler'ie"plas# tic; orjof a gradeofplastic havingsim'ilar qualities.

T he n eedle'- 13 is sealed, whennot' in' use, by'a cover'y tube-30? The cover tube 30' mayr also be`constrn'c'ted' of Marlex or of a grade of plastic having similar frictional qualities, and has a molded end 31, at a right angle to the tubular axis, the opposite end 32 being sealed by pinching olf to leave an interior chamber 33. In assembling the syringe with its cover tube 30, the needle 13 and tube 30 may both be heat-sterilized, the needle may then be forced through the molded end 31 into the chamber 33, and the end 32 may be sealed by pinching. Due to the friction of the plastic upon the needle, the tube 30 will stay upon the needle even when an eiort is made to shake it olf, and of course, the entry by puncture insures that the tube 30 lits the needle 13 with all possible closeness.

Alternatively, the cover tube may be a block 34 of rubber, or like punctnrable and frictional material into which the needle 13 is thrust so as to leave the opening 35 in the end of the needle surrounded and sealed by l'e material of an inner sealing portion 36 of the block yIn operation, the elasticity of the plastic material, coupled with the split formation of the cylinder 10 caused by the keyways or keyway 15, permits a slight yieldmg, either inwardly or outwardly as may be required, of that part of the cylinder from its open end 11 to the ends of the keyways. The elasticity of the material and the shape of the keys 22, lingers 23, and flanges 16, permit the fingers to ride up over the corners 18 and to hold the flanges with a firm grip. The described structure is of great importance when taken with the described materials, as it is seldom possible to mold these materials with the extreme precision that can be applied to machined parts.

When a hypodermic syringe, as hereinbefore described, is pre-filled with a desired medicament and is to be applied to a patient, the cover tube v30 is removed simply by pulling it oi. The keys 2.2 are rotated until the fingers 23 release the llanges 16. At that instant the keys arev in contact with therstops 17 and so are automatically positioned at the entrances of the keyways 15. The` syringe may then be used in the ordinary manner. Because of its low cost it may be thrown away after use. In preparing a large number of syringes for use, as for inoculation against epidemics, they may be sterilized by autoclaving and be left filled, as the plunger cannot be accidentally pushed in or pulled out While the lingers 23 and anges 16 are interlocked.

As modifications will occur to those skilled in the art, the described embodiment is not to be construed as ya limitation upon my invention, the scope of which is deemed to include any desirable constructive modification within the spirit and breadth of the appended claims.

I claim:

l. A hypodermic syringe comprising: a cylinder open at one end and closed at the other end except for the hereinafter mentioned needle; a hollow needle extending from said closed end and communicating with the interior of said cylinder; said cylinder having diametrically opposed longitudinal keyways extending from said open end to points approximately midway between said ends of said cylinder and having outwardly extending flanges at said open end disposed between said keyways; and a plunger litting slidably within said cylinder and having adjacent its outer end diametrically opposed keys, adapted to enter said keyways, said keys having ngers adapted to interlock with said anges to prevent removal of said plunger from said cylinder, said plunger extending inwardly beyond said keyways when said anges and said fingers are interlocked.

2. A hypodermic syringe comprising: a cylinder open at one end and closed at the other end except for the hereinafter mentioned needle; a hollow needle extending from said closed end land having a passage comm-unicating with the interior of said cylinder; said cylinder being formed of hard, slightly elastic material, and

having at least one longitudinal keyway extending from said open end towards said closed end, and having a laterally extending flange at said open end; and a plungi er slidable within said cylinder and having its inner face disposed beyond said keyway and having adjacent its outer end a key slidable within said keyway, said key having a finger adapted to pass over the top of said ange and to interlock therewith, said keyway permitting said cylinder to yield elastically to electuate said interlockmg.

3. A hypodermic syringe comprising: a cylinder open at one lend and closed at the other end except for the hereinafter mentioned needle; a hollow needle extending from said closed end and having a passage communicating with the interior of said cylinder; said cylinder being formed of hard, slightly elastic plastic material, and having at least one longitudinal keyway extending from said open end towards said closed end, and having a laterally extending ilange at said open end; and a plastic plunger slidable within said cylinder and extending normally beyond said keyway and having adjacent its outer end a key slidable within said keyway, said key having a nger adapted to pass over the to-p of said flange and to interlock therewith, said cylinder and said plunger having sufficient elasticity to permit said cylinder to yield at said keyway to effectuate said interlocking and to permit said finger to hold a frictional grip on said ange.

References Cited in the le of this patent UNITED STATES PATENTS 2,551,339 Ryan et al. May 1, 1951 2,626,604 Nadeau Jan. 27, 1953 2,676,591 Fox Apr. 27, 1954 2,844,148 Raife July 22, 1958 FOREIGN PATENTS 614,003 Great Britain Dec. 8, I1948 978,344 France Nov. 22, 1950 740,470 Great Britain Nov, 16, 1955 

